Converts a subset of an array of 8-bit unsigned integers to its equivalent string representation that is encoded with base-64 digits. Parameters specify the subset as an offset in the input array, and the number of elements in the array to convert.

Converts a subset of an array of 8-bit unsigned integers to its equivalent string representation that is encoded with base-64 digits. Parameters specify the subset as an offset in the input array, the number of elements in the array to convert, and whether to insert line breaks in the return value.